Intel Core 2 Extreme QX9650 review

Raising the bar for both performance and power efficiency

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Our Verdict

Intel has taken the wraps off its new flagship 45nm quad-core processor, the Core 2 Extreme QX9650. And that can only mean one thing - a chance to bang on about Moore's law. Again. Well, that and a new performance leader in desktop computing.

Moore's Law, of course, is the so-far accurate prediction made in the 1960s by Intel co-founder Gordon Moore that integrated circuit transistor densities will double every two years.

Indeed, Moore is still going strong today. Intel wheeled him out at the IDF tech jamboree in California this September to reminisce about the good old days. You know, the days when men were men and electrons were gracious enough not to tunnel through insulator layers. Well, you had to be there.

Moore's Law marches on

The relevance of all this is that while AMD struggles to crank out 65nm processors running at competitive clockspeeds, Intel is keeping the faith with Moore. As predicted, the new Core 2 Extreme QX9650 quad-core chip and its 45nm manufacturing tech has arrived within two years of its first 65nm chips. Moore's law marches on.

But what makes this new CPU architecture, previously known under the Penryn codename, tick? The first of a full family of dual and quad-core 45nm chips, the QX9650 is largely a die shrink of Intel's enormously successful 65nm Core 2 processors. However packs a range of enhancements.

Most obvious is a 50 per cent boost in cache memory, now weighing in at 6MB per dual-core die. That's a faintly ludicrous total of 12MB for the quad-core QX9650. Intel is, incidentally, sticking to its existing dual-die setup for quad-core processors.

Then there's the addition of 47 new SSE4 instructions, all the better to speed up the usual multi-media malarkey. The new Radix-16 Divider, meanwhile, is claimed to boost performance in both floating point and integer number crunching.

Super Shuffle

Oh, and there's a new Super Shuffle engine which, again, is said to increase SSE performance along with enhanced sleep modes for power savings and improved virtualisation support, among further detail upgrades.

But it's the revolutionary new 45nm production process that really sets Penryn processors apart. Obviously a smaller production node means higher transistor densities are possible. That's the case with any production shrink.

However, in recent years the power consumption improvements that historically accompanied new processes had begun to dry up. As transistors sizes approach the physical limits of matter, power leakage had begun to spiral out of control.

Gas guzzling be gone

But not with Intel's new 45nm process. As our testing shows, the QX9650 consumes fully 60 Watts less than its identically clocked 65nm predecessor, the QX6850. Given that the typical peak power usage of the QX6850 is probably around 120 Watts, Intel has incredibly managed to cut that chip's gas guzzling in half.

The explanation lies with a pair of revolutionary new materials technologies known as High-K and metal gate. The former refers to a new high resistance material in the insulation layer that sits beneath the transistor gates deep inside the CPU die. Higher, resistance, of course, means fewer electrons seeping through and therefore less power leakage.

The latter refers to a new metal material that replaces polysilicon in the transistor gates and is necessary for optimal compatibility with the new High-K insulator. Together, the result is cooler running, more efficient processors.

Penryn performance

But what about pure performance? Slightly surprisingly given the efficiency of the new 45nm process, Intel has chosen to launch the new chip at 3GHz. That's the same clockspeed as its existing 65nm flagship quad-core chip.

Any performance boost, therefore, must come from those architectural enhancements. In the majority of our benchmarks, the QX9650 delivers five to 10 per cent more performance than its identically-clocked predecessor.

The most notable exception is the DivX 6.7 video encoding benchmark. Courtesy of those additional SSE instructions, the SSE4 path is some 60 per cent quicker. That's extremely impressive, though not likely to be routinely repeated.

Indeed, the only truly disappointing result is probably a function of Intel's new X38 performance motherboard chipset. A memory bandwidth result of just over 7,000MB/s is pretty ordinary given the 1,333MHz of the supporting DDR3 DIMMs. But when the actual performance numbers are this good, does it matter?

Aiming for AMD

Currently, Intel's main rival AMD has nothing to touch Core 2. Given the huge reduction in power leakage, we're confident Intel has several speed bins in hand, ready and waiting for the eventual launch of Phenom, AMD's rather belated quad-core competitor.

It may not be that much faster out of the box. But boy does the new Penryn family pack some promise.

The QX9650 will be available in mid November from the usual online retail suspects for around £650 including VAT.